<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>delete arr</title>
    <script>
        let souce=[85,72,98];
        document.write("删除前数组为："+souce+"<br>");
        document.write("souce[1]="+souce[1]+"<br>");
        document.write("删除后数组为："+souce.splice(0,3,999));
        /*souce.splice(0,3);
        document.write("删除后数组为："+souce+"<br>");*/

    </script>
</head>
<body>

</body>
</html>